Java基礎（有必要記錄一下的程序）

可視化日曆

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Scanner;

public class VisialCalendar {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("請輸入日期(yyyy-MM-dd)");
        String input = scanner.nextLine();

        DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
        try {
            Date date = df.parse(input);
            Calendar c = new GregorianCalendar();
            c.setTime(date);
            int day = c.get(c.DATE);
            c.set(c.DATE,1);
//            System.out.println(c.get(c.DAY_OF_WEEK));//1號的星期數
            System.out.println("日\t一\t二\t三\t四\t五\t六");
            for(int i=0;i<c.get(c.DAY_OF_WEEK)-1;i++){
                    System.out.print('\t');
            }

            for(int j=1;j<=c.getActualMaximum(c.DATE);j++){
                if(j == day){
                    System.out.print("*");
                }
                System.out.print(j+"\t");

                if(c.get(c.DAY_OF_WEEK)==c.SATURDAY){
                    System.out.println('\n');
                }
                c.add(c.DATE,1);
            }
//            System.out.println(c.getActualMaximum(c.DATE));
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }
}
//2019-10-25

輸出文件夾下的所有文件包括子文件夾

import java.io.File;

public class FileTree {
    public static void  printFile(File file,int  level){
        for(int i=0;i<level;i++){
            System.out.print("-");
        }
        System.out.println(file.getName());
        if(file.isDirectory()){
            File[]files = file.listFiles();
            for(File file1 :files){
                printFile(file1,level+1);
            }
        }
    }
    public static void main(String[] args) {
        File f = new File("targetFilesPath");
        printFile(f,0);
    }
}